PDF 数据库备份的问题

db2_all "<<+0< db2 BACKUP DB testdb to /home/db2inst1/BACKUPS"
Backup successful. The timestamp for this backup image is :
20070409100349
Clyde: db2 BACKUP DB testdb ... completed ok

想不明白，为什么要先对0 PARTITION备份，然后在对其他PARTITION进行备份

db2_all "|<<-0< db2 BACKUP DB testdb ONLINE to /home/db2inst1/BACKUPS"
rah: omitting logical node 0
Backup successful. The timestamp for this backup image is :
20070409100510
Clyde: db2 BACKUP DB testdb ... completed ok
...收起